Description

Komatsu PC800, PC800LC, PC800SE, PC850, PC850SE Installation Manual

If you are assembling a PC800, PC800LC, PC800SE, PC850, or PC850SE from a knocked-down kit, you need more than a prayer and a crescent wrench. I have seen field-assembled machines leak hydraulic oil because someone guessed on the torque for a travel pipe flange. That guess cost a shop two days of downtime and a customer screaming about lost production. This 189-page Komatsu PC800, PC800LC, PC800SE, PC850, PC850SE Installation Manual is the OEM document that tells you exactly how to put these excavators together right the first time.

Tightening Torque: Where Most Field Assemblies Fail

Torque values live on page 13 of the TIGHTENING TORQUE chapter. That page lists specs for every fastener you will touch during assembly — track frame bolts, travel pipe fittings, boom cylinder pins, and counterweight retainers. I have used aftermarket “generic” torque charts that list 250 ft-lbs for a M30 bolt that actually calls for 310 ft-lbs. You get that wrong, the joint loosens under vibration. Then you are bleeding air or chasing a leak. The manual’s torque table breaks it down by bolt grade and thread pitch. Use a calibrated torque wrench. No exceptions.

7 Major Assembly Sections You Need to Follow

This manual does not waste time. It splits the job into four main sections plus a separate counterweight remover procedure and a final inspection checklist. You get:

• A. Assembly of Chassis – Left and right track frames, travel pipe, top guard, radiator cover, rearview mirror, left side step, handrails, muffler tail tube, counterweight installation, KOMTRAX antenna (if equipped), step light, travel motor air bleeding, travel piping cover, track shoe tension check, and fluid level checks.
• B. Assembling of Work Equipment of Backhoe – Arm cylinder assembly, boom cylinder foot, relieving hydraulic pressure, boom assembly, hose connections for arm and bucket circuits, quick return hose, boom cylinder, arm assembly, bucket assembly, lubrication piping, wiring, greasing, and air bleeding from cylinders.
• C. Assembling of Work Equipment of Loading Shovel – Similar procedures for the shovel configuration, including boom and arm assembly, flushing piping for bucket and bottom dump cylinders, working lamps, grease piping, and air bleeding.
• D. Assembling of Counterweight Remover – Rubber cushions, shim adjustment, greasing, covers, hoses, and counterweight installation.
• M. Procedure for Inspection and Maintenance after Completion of Assembly – Oil level checks, return filter replacement (standard to flushing filter), flushing of hydraulic circuit, filter replacement back to standard, and failure code interpretation.

Each procedure has its own sub-steps with page references. For example, the travel pipe installation starts on page 26. That page includes the torque sequence for the pipe clamps. If you skip the sequence, you get pipe stress and eventual cracks.

Who Should Use This Manual?

This is for dealership field service technicians, heavy equipment mechanics who rebuild excavators, and shop owners who take on Komatsu kit assembly jobs. It is also for experienced DIYers who buy a used PC800 or PC850 that arrived in pieces and needs reassembly. Beginners should not attempt this without a mentor — the manual assumes you know how to handle hydraulic pressure, wire rope selection, and lifting procedures. The PRECAUTIONS FOR FIELD ASSEMBLY chapter on page 2 covers safety basics: relieve residual pressure before disconnecting lines, use the proper lifting points listed in the SELECTION OF WIRE ROPES USED FOR ASSEMBLY chapter (page 20), and never exceed the rated capacity of your slings.

OEM Document vs Aftermarket PDFs

I do not trust aftermarket documentation on principle. Third-party shops that scan and resell manuals often crop out pages, reduce image resolution, or omit the TIGHTENING TORQUE chapter because they cannot OCR the table correctly. This Installation Manual is a direct digital copy of the official Komatsu publication. The serial number range (65001 and up for PC800-8E0, PC800LC-8E0, PC800SE-8E0, PC850-8E0, PC850SE-8E0) is stamped on the cover. You get the exact same instructions that Komatsu delivers to dealerships. For deeper engine and hydraulic diagnostics, pair this with the Komatsu PC800/PC850 Workshop Manual – Factory Specs, 1327 Pages. If your PC750 or earlier PC800 needs overhaul specs, grab the Komatsu PC750/PC800 Workshop Manual 2004 — 730 Pages OEM Specs. For wheeled excavators, the Komatsu WD900-3 Installation Manual – Field Assembly Specs & OEM Torque covers similar procedures.

FAQ: Common Questions About This Manual

Does this manual cover the PC800-8E0 with the ecot3 engine?

Yes. The cover explicitly lists PC800-8E0, PC800LC-8E0, PC800SE-8E0, PC850-8E0, and PC850SE-8E0. These models all use the Komatsu ecot3 engine family. The manual includes hydraulic circuit bleeding steps that apply to that engine’s hydraulics.

What torque specs are included?

The TIGHTENING TORQUE chapter on page 13 provides values for all fasteners used in field assembly. It covers track frame bolts, travel pipe fittings, cylinder mounting bolts, and counterweight bolts. The table is metric, with newton-meter and foot-pound equivalents. You need a torque wrench that reads in ft-lbs or Nm.

Can I use this manual for a PC850SE with a loading shovel attachment?

Section C covers assembling work equipment for a loading shovel configuration. It includes steps for boom and arm assembly, bucket cylinder piping, bottom dump cylinder hoses, working lamps, and grease piping. The same manual covers both backhoe (Section B) and loading shovel (Section C) equipment.

Does it include the field assembly inspection report?

Yes. The last pages contain two FIELD ASSEMBLY INSPECTION REPORT forms: one for backhoe and one for loading shovel. These checklists verify torque, fluid levels, hydraulic circuit flushing, and failure codes. You sign off after completing the inspections.

Look, I have been wrenching on Komatsu equipment since the late 1990s. The difference between a machine that works for 8,000 hours without major hydraulic issues and one that starts leaking at 500 hours often comes down to using the right installation manual. Do not trust a third-party PDF that might have wrong torque values. Access the Factory Manual from AutoRepairManuals and keep it open on your tablet or printed out while you assemble. Your wallet — and your customer — will thank you.